COPD is a common, progressively disabling disease and a major health burden worldwide. The disease is a disabling and complex disease and a major public health problem worldwide as it affects an estimated 600 million people and ranks within the top 5 leading causes of death. The disease is characterised by partially reversible airflow obstruction driven by in situ inflammatory changes and airway wall remodelling. Consequently COPD patients have a poor quality of life, aggravated by acute distressing flare-ups. These infective/inflammatory exacerbations increase with disease severity, occurring on a background of variable but progressive natural decline in the patient's lung function.
Currently COPD is measured at particular points in time and this gives an indication of the disease state at that point. There is currently no routine near-patient sensitive tools to monitor COPD, and more specifically how to predict, which COPD patients are more prone to rapid deterioration in lung function and to increased exacerbations. COPD ‘flare-ups’ are diagnosed usually on clinical grounds; including a deterioration in specific symptoms (e.g. shortness of breath). Currently measurements of a patient's condition are made using forced expiratory volume in one second (FEV) measurements following bronchodilation, but these measurements are not predictive of disease progression or outcome. Assessment of COPD has been made by bronchial/lung biopsies and bronchoalveolar lavage but whilst greatly advancing knowledge of COPD status, such measures are not amenable to everyday use. Spontaneous and induced sputum analysis has also been performed using a mix of biological technologies and recent progress with exhaled breath analysis looks promising but is limited by high magnitude inter-patient differences in exhaled volatile organic compounds and nitric oxide markers, very low levels of which are not easily detected, so potentially reducing routine clinical value of this biomarker. Thus current methods are in early stage research or at the preclinical trial stage or just not amenable to clinical so leaving a clinical need and challenge to identify patients with COPD in an effective, practical and non-invasive way to enable determination and monitoring of disease status with sufficient sensitivity to give early warnings of exacerbations of the disease.
Fourier transform infrared spectroscopy (FTIR) is a non-invasive technology that can detect structural changes in molecules from tissue or cells. Such changes can be visualized using a spectrum of wave numbers usually taken from the mid infrared range (4000 to 400 cm−1). FTIR has shown promise as a sensitive diagnostic tool to distinguish neoplastic from normal cells in cancers such as colon cancer, prostate, breast, cervical, gastric, oral and oesophageal cancer. In these and other studies, biochemical changes are often observed between tumour and normal cells within a wavenumber range known as the “fingerprint region” (encompassing 1800 to 950 cm−1). Whilst FTIR has proven applicability in other disciplines FTIR analysis has not been applied to address the clinical needs of COPD where spectral profiles of human sputum are made to identify differences between COPD and health.
The present invention seeks to overcome the problems that currently exist with monitoring COPD by providing an easy to use analysis process which can be used to analyse the stage of and progression of COPD so appropriate treatment can be provided for a patient according to their particular condition. Spectroscopy methods such as FTIR and variable filter infrared spectroscopy (VFIR) can be used.